Systems and methods of managing metameric effects in narrowband primary display systems

ABSTRACT

Several embodiments of display systems that use narrowband emitters are disclosed herein. In one embodiment, a display system comprises, for at least one primary color, a plurality of narrowband emitters distributed around the primary color point. The plurality of narrowband emitters provides a more regular power vs. spectral distribution in a desired band of frequencies.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of priority to related, co-pendingProvisional U.S. patent application No. 61/506,549 filed on 11 Jul. 2011entitled “Systems and Methods of Managing Metameric Effects inNarrowband Primary Display Systems” by Eric Kozak, et al. herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to displays systems and, moreparticularly, display systems—including projector systems and directview systems or others—that may employ narrowband lighting.

BACKGROUND

Typically, display systems generate images from three or more primarycolors. Some light sources (e.g. LED, OLED, laser especially) can onlyproduce a narrow range of wavelength. Each primary will be emitted froma separate source (or group of sources). The light from all the sourcesin the system can be mixed in varying quantities to generate any colorwithin the gamut of the primaries (e.g., by using Grassman's Law ofAdditivity).

Characteristically, lasers and LEDs/OLEDs have a very narrow spectrumaround a center frequency (or inversely, the wavelength), so the coloredlight that is produced contains only substantially a very exact color.

Human beings all view color slightly differently, i.e. different peopleare more sensitive to certain hues of reds, greens, and blues. Humanscan be thought to have color filters embedded in their eyes which yellowslightly with age. Thus, when two observers look at an identical veryspecific hue of red (or other color) they may report differentintensities relative to other colors observed in the ambientenvironment.

This effect may be compounded by colors generated by narrow spectrumsources. With a display system comprised of narrow band primaries, twoobservers may perceive different projected colors due to slightvariances in cone wavelength sensitivity. This effect is often referredto as “metameric failure”, and may not be desirable by the designers ofdisplay systems comprising narrow spectrum sources.

SUMMARY

Several embodiments of display systems and methods of their manufactureand use are herein disclosed. Such display systems may encompass allmanners of displays—e.g. projector systems, direct view systems and thelike.

In one embodiment, a projector system is disclosed, designed to emitlight from a plurality of primary colors. For at least one such primarycolor, the projector system further comprises a plurality of narrowbandemitters grouped approximately around a single wavelength or frequencyof such primary color. The plurality of narrowband emitters areintentionally selected to provide, collectively, a slightly wider bandof wavelengths or frequencies than might be achieved by random selectionof emitters around the same primary color.

In yet another embodiment, a direct view display is disclosed, designedto emit light from a plurality of primary colors. For at least one suchprimary color, the projector system further comprises a plurality ofnarrowband emitters grouped approximately around a single wavelength orfrequency of such primary color. The plurality of narrowband emittersare intentionally selected to provide, collectively, a slightly widerband of wavelengths or frequencies than might be achieved by randomselection of emitters around the same primary color.

In yet another embodiment, a display system comprising a plurality ofnarrowband emitters, intentionally selected as noted, may be employed byturning on a selected subset of the plurality when colors in an imageare displayed that are near the edge of the color gamut of the displaysystem.

Other features and advantages of the present system are presented belowin the Detailed Description when read in connection with the drawingspresented within this application.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be considered illustrative rather than restrictive.

FIGS. 1A and 1B show two alternative embodiments of a projector systemthat employs a plurality of narrowband emitters to provide at least oneprimary color.

FIG. 2A depicts a power vs. spectrum frequency distribution for oneexemplary narrowband emitter.

FIG. 2B depicts the power vs. spectrum frequency distribution for asubstantially random collection of narrowband emitters, centered about aprimary color.

FIG. 3 shows the power vs. spectrum frequency distribution for aplurality of narrowband emitters that are substantially equallydistributed about one primary color and with sufficient number so as toachieve a desired band of frequencies about the primary color.

FIG. 4A shows one embodiment of a direct view display system comprisinga narrowband emitting backplane and a diffuser.

FIGS. 4B and 4C shows two embodiments of a package of narrowbandemitters that might comprise the illumination backplane of a direct viewdisplay system.

FIGS. 5A and 5B shows two embodiments of transmitted light emitted bynarrowband emitters from a backplane to a liquid crystal array.

FIG. 6 shows one embodiment of color gamut of a display system inside ofthe conventional CIE chromaticity chart.

FIG. 7 shows a block diagram of one embodiment of a system for drivingnarrowband emitters.

FIGS. 8A-8C show one embodiment of selectively turning on narrowbandemitters.

DETAILED DESCRIPTION

Throughout the following description, specific details are set forth inorder to provide a more thorough understanding to persons skilled in theart. However, well known elements may not have been shown or describedin detail to avoid unnecessarily obscuring the disclosure. Accordingly,the description and drawings are to be regarded in an illustrative,rather than a restrictive, sense.

One Embodiment-Projector Systems

FIG. 1A shows one embodiment of a projector system 100 that comprises aplurality of narrowband (NB) emitters (102 a, 102 b, 102 c) that aregrouped around at least one primary color. Projector system 100 may havemany primary colors that are employed to provide a full color gamut tothe viewer—and it may be desirable for the projector system to havepluralities of narrowband emitters, as intentionally selected asdescribed herein, for each primary color designed into the projectorsystem—but, for purposes of the present application, it may besufficient that there is only one primary color for which there is aplurality of narrowband emitters that are intentionally selected.

There may be several reason why a projector system designer might use aplurality of emitters around a given primarily—e.g. to increase theluminance of the projected image for a satisfying visual experience in,say, a movie theatre. For example, modern display systems have the addeddemand of increased luminance due to the proliferation of 3D movies(glasses attenuate light), larger screens (reduces average light in anarea), and the desire for more stunning on-screen images. Laserprojectors may employ multiple lasers for each primary to economicallyincrease the amount of light output by the projector and thus brightenthe projected image.

In the case of laser projector systems, another reason might be toreduce the effect of speckling that may be attendant with laser producedlight. In the case of LED backlit displays, there are often a great manyLEDs spatially distributed representing each primary.

Assuming each emitter 102 a, 102 b and 102 c emit substantially around asingle primary color (and its characteristic wavelength or frequency)and assuming that there may be other emitters (not shown) that emitlight for other primary colors designed into the projector system, thelight from each of these emitter may be combined into an optical path,perhaps by an optional integrating sphere 104 and sent into an opticalpath 106 which may comprise any number of lenses or other opticalelements (not shown), according to the dictates of the system designers.As may be designed into a projector system, the light may be sent to aset of DLP reflectors 108 and subsequently displayed on a screen 110—topresent an image to set of viewers in a variety of settings, forexample, a movie theatre, home projector system or the like.

It will be appreciated that many different types of projector systemsmay be designed, employing a plurality of narrowband emitters for atleast one primary color—and that the scope of the present application isnot limited by the recitation of one such projector systems. In fact,other suitable projector systems may be rear projector, front projectionor the like.

FIG. 1B shows another alternative embodiment of a projector system 100as shown in FIG. 1A. In this embodiment, liquid crystal resonator cavity(LC cavity) 103 a, 103 b, 103 c are placed in the path of lightemanating from narrowband emitters 102 a, 102 b and 102 c and arrivingat integrating sphere 104. Controller 105 is shown, sending controlsignals (e.g. voltage signals) to each such LC cavity. As is known, LCcavities have certain characteristics such as polarization change whichin turn can shift laser wavelengths as a function of applied voltage.Controller 105 may also comprise suitable hardware, firmware and/orsoftware to allow for the calibration of the display system. Inaddition, controller 105 may contain suitable hardware, firmware and/orsoftware to determine image data content and characteristics—e.g.chromaticity, color saturation, luminance, etc.

As discussed further below, such wavelength modulations may allow thedesigner of the projector system to have control over a number ofvariables for image rendering. For example, the frequencies of the lightfrom the NB emitters may be modulated by the LC cavities to have moreaccurate, and even spectral spacing between each other. In addition, LCcavity modulation may dynamically alter the spacing of the NB emitterlight to control the bandwidth of the light collectively from theplurality of NB emitters.

As shown in FIG. 1B, the LC cavities may have separate voltages appliedto them which is controlled either by a calibration system or by adisplay rendering algorithm. For the calibration system approach, thecenter wavelengths of the installed emitters may be measured, andvoltages are then applied in a fixed manner in order to spread out theemitter wavelengths according to the goal of minimizing metamerism.

When under control of the display rendering algorithm, the voltages aredetermined based on the image content. If there is not a substantialamount of highly saturated content, then the voltages may be set tospread the center wavelengths apart to reduce metamerism. Conversely, ifthere is substantially little or no desaturated content, then thevoltages may be applied such that they are shifted to be as closetogether as possible. As will be discussed further with regards to FIG.6 below, this may enable a wider color gamut, and if there are nodesaturated colors, the metamerism problem is less noticeable due to theHuman Visual System (HVS) having elevated thresholds for distortion forsaturated colors.

Although FIG. 1B discloses one embodiment for the tuning of lightfrequencies and/or wavelengths (i.e. LC cavities) in order to controlthe spacing of the narrowband emitters (either for calibration or imagerendering), it will be appreciated that there are several other knownapparatus and techniques for tuning the wavelengths of such narrowbandemitters. For example, the techniques of Optical Parametric Oscillation(OPO), the use of non-linear crystals, piezoelectric crystaloscillators, and the use of dye-tunable lasers are all suitableapparatus and methods of tuning the light of narrowband emitters for thepurposes of the present application. The scope of the presentapplication encompasses all of the above and other known apparatus andmethods. Broadly, these known techniques may be referred to a“wavelength tuners” for the purpose of the present application.

FIG. 2A shows a mapping of power vs. spectral frequency for a singlenarrowband emitter, such as a laser, LED, or OLED emitter. As may beseen, the power is sharply peaked at substantially a single frequency,f₀. In the case of lasers, current laser fabrication techniques andoperating conditions yield lasers that have their center frequenciesdiffering from an ideal frequency within a tolerance range, i.e. alllasers are not exactly the same, but they all fall within astatistically predictable group. Thus, when several lasers of one colorare grouped together, they will have a random distribution of beamcenters generating a non-uniform spectrum. The same may be substantiallysaid of LED and OLED emitters.

FIG. 2B shows a mapping of power vs. spectral frequency for a pluralityof single narrowband emitters, each emitter constructed to conform to asingle primary (e.g. red at 650 nm wavelength). Each emitter may haveslight variation from 650 nm—with the resulting power vs. spectralfrequency mapping to be irregular (as shown) and with a slightly largerband than a single narrowband spread.

If the plurality of single narrowband emitters is intentionally chosen,then a wider and more even and/or regular band of emission may beaffected. FIG. 3 shows a plurality of intentionally chosen narrowbandemitters (say, {e₁, e₂, . . . e_(n)} emitting at center frequencies (f₀,f₁, . . . , f_(n)) for example)—in this embodiment, each emitter may besubstantially evenly spaced and given in a sufficient number to providea substantially even power distribution across a desired band ofspectrum presented. In one embodiment, each adjacent pair of emitters{e_(i), e_(j)} may have substantially the same spectral distance whencompared to any other adjacent pair of emitters.

In another embodiment, the number of emitters may be determined by thespectral distance of the band, d₁, divided by the substantially regularspacing of the emitters. For merely exemplary embodiments, spectralwidth or distance, d₁, might comprise a range of 18-33 nm. Otherembodiments may have different spectral widths for different primarycolors—e.g. 18 nm for red, 25 nm for blue and 33 nm for green. Thesewidths may vary, depending upon the amount of metamerism might bepresented by these (and other) primary colors. In addition, the widthmay be dependent upon the type of application for the given displaysystem—e.g. a laser projector for cinema, a laser projector or LEDdirect view for home, etc.

Employing such a plurality of narrowband emitters allows for a broaderspectrum for each primary color generation. Due to the broader spectrum,observers with slightly different cone sensitivities may not disagree onperceived colors from the projection system, thus avoiding metamericfailure.

In one embodiment, these pluralities of narrowband emitters may beselected in a production facility by use of effective binning techniques(e.g. testing fabricated lasers or LEDs and grouping them based onemitted frequency). While this may tend to shift the color primariestoward the neutral point away from the spectral locus, and thus maycause a reduction in the color gamut, the technique allows for a carefultradeoff between color gamut and stability under individual metamerismvariability.

Second Embodiment- Direct View Displays Systems

The same principal can be applied to LED backlit LCD displays and OLEDdisplays where LEDs can be selected (e.g. from production bins) togenerate a wider primary spectrum. In this case, LEDs on the backlightwould have the wavelength bin taken into account during placement toensure geographic areas were not devoid of certain wavelengths. In adirect view OLED application, the primaries of each triplet pixel wouldbe consistently varied across the screen such that when multiple pixelsdisplay a color a wider spectrum would be guaranteed.

For another embodiment, FIG. 4A depicts a simplified view of an LCDdirect view display 400. Display 400 may be broadly construed as havinga LED backplane 402, further comprised of LEDs—either individuallyplaced or in packages, such as package 406. In addition to the LEDbackplane 402, newer LCD displays that effect a local dimming featuremay further comprises diffuser 404 in order to create a better blendingof colors and avoid “hot spots” of illumination, visible through aliquid crystal layer (not shown).

FIG. 4B shows one embodiment of LED package 406 a—in this case, oneconstructed of two green emitters, one red and one blue emitter. Ifthese packages are sufficiently densely populated throughout thebackplane 402, then effective distribution of a plurality ofindividually chosen emitters may provide a modicum of protection againstmetameric failure as described above. In yet another embodiment, FIG. 4Cshows one package 406 b in which the plurality of narrowband emitters isplaced within a package 406 b—e.g. R1, R2, R3 and R4.

FIG. 5A shows in better detail in interaction of LEDs 502, then light506 emitted by one such LED 502, diffuser 506—and the resulting pointspread function (PSF) that subsequently illuminates a group of LCDsubpixels spatially located to receive the illumination (not shown).

Yet another known manner of providing illumination to spatially locatedsubpixels is shown in FIG. 5B. A group of LEDs (or other narrowbandemitters) 502 are grouped to one side of a tile waveguide 510. Asillumination 504 from one of the emitters 502 couples with the tilewaveguide 510, the resultant illumination 512 is shown. As may be seen,illumination 512 is more evenly and regularly distributed spatially tolocal LCD subpixels (not shown) than the PSF given by a diffuser. Evenin this situation, one embodiment of a display system may comprise aplurality of narrowband emitters, intentionally and evenly distributedin its spectral power curve, for the reasons herein discussed.

FIG. 6 depicts the standard CIE chromaticity chart 600 and an assumedcolor gamut 602 of a display system as described herein. As is shown inthis one embodiment, each primary color, R, G, B uses a plurality ofnarrowband emitters (e.g. r₁, r₂ . . . r_(n), g₁, g₂. . . g_(n), b₁, b₂. . . b_(n)) at the corners of the color gamut. If all of the narrowbandemitters were turned on, the color gamut would be smaller—as shown, forexample, as gamut 604. As the display system is in operation andrendering color images, most image values will have their chromaticitypoints somewhere comfortably within the color gamut of the display, suchas point 610. When rendering such point 610, the system may use theillumination of the plurality of narrowband emitters to the effect asdescribed herein. It should be appreciated that the emitter frequenciesare not necessarily drawn to scale on FIG. 6—for example, the emitterfrequencies might be grouped in manner a much tighter around a primaryvalue than shown. In addition, the placement of the narrowband emittersmay be different than what is shown in FIG. 6—for merely one example,the green emitters may be placed closer to the top of the CIE chart.

However, as the display system detects that an image value (e.g. point612) is approaching the extremes of the color gamut of the display (orperhaps even out of gamut), it may be desirable that the display systemuse only one (or a small number) of narrowband emitters to illuminatethat image value. For example, to create image value 612, it may bedesirable to employ only one green emitter (say, g_(j), for some j) andone blue emitter (say, b_(i), for some i) to render the color value ofpoint 612, which may be a deep cyan value.

Embodiment For Driving Narrowband Emitters

For the embodiments above, it suffices that there is a set ofintentionally selected narrowband emitters for at least one primary ofthe display system. The display system can drive these narrowbandemitters in any manner known in the art. However, given the design ofthese embodiments, there may be an opportunity to drive these narrowbandemitters advantageously, depending upon the image data to be rendered bythe display system.

FIG. 7 shows a block diagram of one embodiment of a driver for at leastone plurality of narrowband emitter in a display system.

Driver inputs image data—here shown as an input color triplet (e.g. RGB,XYZ, YCrCb or the like)—however, it should be appreciated that thetechniques and system can be expanded to drive a multiprimary system ofany number of different primary colors desired. Driver may calculate thecolor saturation radius at 702 and luminance of the image data at 704.Once the color saturation radius of the image data is determined and/orderived, the driver may calculate the number of narrowband emitters thatmay suffice for each primary color (at least those having theintentionally selected emitters) at 706. For each NB emitter, aluminance value may be known—and as the luminance is additive formultiple emitters, the luminance of the emitters are compared ormeasured against the luminance derived, calculated or otherwise dictatedby the image data at 710. If the luminance of the lit emitters is notenough for the luminance of the image data, then other emitters may beturned on. As these emitters are turned on, they may be driven to theirmax luminance—or any other luminance value desired; but in at least oneembodiment, the max luminance may be tried initially for lit emitters at708.

In operation, however, driver could proceed as follows: as the overallprimary needed to be raised for brighter input primary values, more andmore of the binned primaries would be added (per the needs of eachprimary vertex) to reach the needed light level. However, driver mayproceed differently if metamerism problems may be present.

For merely one example, metamerism problems may arise when the primaryvalues are low (e.g. darks and neutral values). In such a case, it maybe desired that, as the chroma (e.g. color saturation radius) increases,driver may reduce the number of narrowband emitters used, even thoughthis may run counter to the desire to turn on more emitters to achieve ahigher primary luminance value—e.g. whichever one is closest to thecolor needing high saturation.

However, to keep the color from being desaturated due to the spreadingof spectral width of the primary, driver may turn on less narrowbandemitters. Thus, in one embodiment, driver may drive a set of chosenemitters stronger. The driver may determine the chroma (color saturationradius) of the image data. Then, the driver may determine the number ofnarrowband emitters to turn on for that saturation (e.g. for more colorsaturation , perhaps use less narrowband emitters). But then the drivermay check to see if a set of emitters can meet the desired luminance ofthe image data. If not, the driver may add more narrowband emitters(i.e., at or around the same primary vertex position). For non-saturatedcolors, especially white, it may be desired to turn on more emitters (ata lower amplitude if needed) in order to reduce metamerism variability.

If the driver determines that there is sufficient luminance due to theselected narrowband emitters, the driver may then scale the overallvalues down of all narrowband emitters per vertex (and this may be donefor all in the primary vertex; i.e. the R primaries for example) to getthe input color at 712.

In another embodiment of a driver, FIGS. 8A through 8C depict oneembodiment of a desired manner to turn on narrowband emitters to achievesatisfactory luminance and saturation. In FIG. 8A, one desirednarrowband emitter is turn on (for example, 802). This desired emittermay be, for example, the one closest to the primary color specified forthe display. Alternatively, the desired emitter could be the one closestto the chromaticity of the image data. If more emitters are desiredand/or needed for, e.g. luminance, then FIG. 8B and 8C show that asecond and then a third emitter may be turned on that are perhaps secondand third closest to the specified primary color, respectively 804 and806. This process may continue until satisfactory luminance for theimage data is realized.

A detailed description of one or more embodiments of the invention, readalong with accompanying figures, that illustrate the principles of theinvention has now been given. It is to be appreciated that the inventionis described in connection with such embodiments, but the invention isnot limited to any embodiment. The scope of the invention is limitedonly by the claims and the invention encompasses numerous alternatives,modifications and equivalents. Numerous specific details have been setforth in this description in order to provide a thorough understandingof the invention. These details are provided for the purpose of exampleand the invention may be practiced according to the claims without someor all of these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

1. A display system comprising: a set of narrowband emitters, said setof narrowband emitters capable of producing illumination for saiddisplay system to produce displayed images; said set of narrowbandemitters further comprising at least one plurality of narrowbandemitters, said at least one plurality of narrowband emitters emittinglights selected in frequency substantially near a first primary color;and wherein further said at least one plurality of narrowband emitterscomprise a set of narrowband emitters {e₁, e₂, . . . e_(n)} and furtherwherein each adjacent pair {e_(i), e_(i+1)} has substantially the samespectral distance.
 2. The display system as recited in claim 1 whereinsaid display system comprises a laser projector.
 3. The display systemas recited in claim 2 wherein said laser projector system furthercomprises: an integrating sphere, said integrating sphere inputtinglight from said at least one plurality of narrowband emitters.
 4. Thedisplay system as recited in claim 1 wherein said display systemcomprises a direct view display.
 5. The display system as recited inclaim 4 wherein said direct view display further comprises: a pluralityof narrowband LED emitters; and a diffuser.
 6. The display system asrecited in claim 4 wherein said direct view display further comprises: aplurality of narrowband LED emitters; and a plurality of tilewaveguides.
 7. A display system comprising: a set of narrowbandemitters, said set of narrowband emitters capable of producingillumination for said display system to produce displayed images; saidset of narrowband emitters further comprising at least one plurality ofnarrowband emitters, said at least one plurality of narrowband emittersemitting lights selected in frequency substantially near a first primarycolor; and wherein further said at least one plurality of narrowbandemitters emit a substantially even power distribution in a desired bandwhen said at least plurality of narrowband emitters are turned on. 8.The display system as recited in claim 7 wherein said desired bandcomprises the range of substantially 18 nm to 33 nm.
 9. The displaysystem as recited in claim 8 wherein said display system is one of agroup, said group comprising: a laser projector and a LED direct viewdisplay.
 10. A method for driving a display system, said display systemcomprising at least one plurality of narrowband emitters, said at leastone plurality of narrowband emitters emitting lights selected infrequency substantially near a first primary color such that said atleast one plurality of narrowband emitters emit a substantially evenpower distribution in a desired band when said at least plurality ofnarrowband emitters are turned on, the steps of said method for drivinga display system comprising: inputting image data; calculating inputimage data color saturation values; calculating input image luminancevalues; and selectively determining which narrowband emitters to turnon, depending upon the calculated saturation and luminance values of theinput image data.
 11. The method as recited in claim 10 wherein saidstep of selectively determining which narrowband emitters to turn onfurther comprises: selecting an initial set of narrowband emitters toturn on to an initial luminance value, depending upon the colorsaturation of the input image data, comparing the luminance of saidinitial set of narrowband emitters to the luminance value of the inputimage data; driving the initial set of narrowband emitters to aluminance value higher than the initial luminance value, if the sum ofthe initial luminance value of the initial set of narrowband emitters islower than the luminance value of the input image data.
 12. The methodas recited in claim 11 wherein said method further comprises the stepof: turning on at least one additional narrowband emitter, if the totalluminance of the initial set of narrowband emitters at maximum luminanceis lower than the luminance value of the input image data.
 13. Themethod as recited in claim 10 wherein said method further comprises thestep of: selectively decreasing the number of narrowband emitters if thecolor saturation of the input image data increases.
 14. A method ofselectively turning on emitters in a display system, said display systemfurther comprising at least one plurality of narrowband emitters, saidat least one plurality of narrowband emitters emitting lights selectedin frequency substantially near a first primary color such that said atleast one plurality of narrowband emitters emit a substantially evenpower distribution in a desired band when said at least plurality ofnarrowband emitters are turned on, the steps of said method for drivinga display system comprising: (a) turning on a first narrowband emitter,said first narrowband emitter being substantially closest in frequencyto said first desired color; (b) If maximum luminance of said firstnarrowband emitter is lower than the luminance of the input image data,turning on a next narrowband emitters, said next narrowband emitterbeing substantially the next closest in frequency to said first desiredcolor; and (c) Repeating step (b) until the maximum luminance of saidnarrowband emitters is substantially equal to the luminance of the inputimage data.
 15. The method as recited in claim 14 wherein said firstdesired color is the primary color of said display system.
 16. Themethod as recited in claim 14 wherein said first desired color is aprimary color comprising the chromaticity of the input image data.
 17. Alaser projection display system comprising: a set of narrowbandemitters, said set of narrowband emitters capable of producingillumination for said display system to produce displayed images; saidset of narrowband emitters further comprising at least one plurality ofnarrowband emitters, said at least one plurality of narrowband emittersemitting lights selected in frequency substantially near a first primarycolor; a set of wavelength tuners, said wavelength tuners opticallycoupled to receive light from said at least one plurality of narrowbandemitters; and a controller coupled to said set of wavelength tuners,said controllers sending control signals to said set of wavelengthtuners to modulate the frequency of the light emitted by said at leastone plurality of narrowband emitters.
 18. The laser projection displaysystem as recited in claim 17 wherein said set of wavelength tuners ispaired with said plurality of narrowband emitters on a one-to-one basis.19. The laser projector display system as recited in claim 18 whereinsaid wavelength tuner comprises one of a group, said group comprising:LC cavity, optical parametric oscillator, piezoelectric crystaloscillator, non-linear crystal and dye-tunable laser.
 20. The laserprojection display system as recited in claim 18 wherein said controllersends control signals to separately modulate the frequency of each ofsaid plurality of narrowband emitters.
 21. The laser projection displaysystem as recited in claim 20 wherein said controller sends controlsignals to modulate the frequency of each of said plurality ofnarrowband emitters such that the frequencies of said plurality ofnarrowband emitters are grouped closer together, if the image data to berendered comprises substantially little or no desaturated content. 22.The laser projection display system as recited in claim 20 wherein saidcontroller sends control signals to modulate the frequency of each ofsaid plurality of narrowband emitters such that the frequencies of saidplurality of narrowband emitters are grouped further apart, if the imagedata to be rendered comprises substantially little or no saturatedcontent.